Direct-acting pump.



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PATENTEDMAY 28, 1907.

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N0- 855,150- I PATENTED MAY 28, 1907. I W. WEIR. I "DIRECT ACTING PUMP.APPLICATION FILED 001mm, 1905.

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WILLIAM WEIR, OF OATHOART, SCOTLAND.

DIRECT-ACTING PUMP.

Specification of Letters Patent.

Patented May 28, 1907.

Application filed October 21,1905. Serial No. 283,763.

To all whom it may concern:

Be it known that 1, WILLIAM WEIR, a subject of the King of the UnitedKingdom of Great Britain and Ireland, residing at Cathcart, county ofRenfrew, Scotland, have in vented certain new and useful Improvements inDirect-Acting Air-Pumps, of which the following is a specification.

This invention relates to improvements in direct-acting air pumps of thesingle acting type where these are driven by direct-acting steamcylinders, and is designed more particularly to render the working ofthese more efficient, more economical in steam consum tion, morecompact, and less variable in tl ie relative speed of the upward anddownward strokes.

It is well known that the working of single acting air pumps when drivenby direct double acting steam cylinders is unsatisfactory on accountofthe great diflerence in the load on the air pump bucket on the upwardand downward strokes.

My improvements are applicable to single acting air pumps driven bydirect acting steam cylinders which may be fitted with any suitable typeof steam actuated valve, but which are preferably provided with a valveof the character herein shown and described.

The invention is illustrated by the accompanying drawings of whichFigure 1 shows a single single-acting air pump driven by a singledirect-acting steam cylinder fitted with steam actuated valve, and withmy improvements, Figs. 2 and 3 are sections across the line X, Y of Fig.1 and represent plan views to a larger scale of a steam actuated valveof the Weir type arranged with my improvements for driving the steamcylinders of single direct-acting air pumps, the valves being shown indifferent positions. Figs. 4 and 5 are sectional views looking on theback of the main valve. Fig. 6 is a cross vertical section of the steamdistribution chest and valves.

In Fig. 1, A is the air pump of the usual type with foot bucket and headvalves, or alternatively of the suction valveless type having only headvalves. B is the steam cylinder and C the steam actuated valve chestwith usual valve gear M.

According to one modification the steam cylinder B is arranged with theusual ports H and J leading from the steam actuated valve inderrespectively.

Referring to Fig. 2 which shows the steam actuated valve F in such aposition that the steam piston K, Fig. 1 is at the bottom end ofitsstroke and commencing its upward stroke, steam is admitted to thevalve chest through the supply branch D then through the port H on thevalve face N, (this port being open above the valve G, Fig. 5) then intothe cavity H through the port H port H port H, and thus to the cylinderB below the piston K causing it to make its upward stroke. At the sametime the steam on the upper side of the piston K, is exhausted to theatmosphere or condenser through the orts J, J J J into E, the finalexhaust out et. After making the upward stroke the piston K comes to thetop end of the cylinder and the valve F is thrown over and reversedinthe usual manner of the Weir valve and takes the position shown in Fig.3 through the intermediary of the valve G, the operation of which is asfollows:* On the upward stroke of the piston K. the valve G is moved inthe same direction and at the same time, until the small cavity U in thevalve G, Fig. 4, covers the ports V and T and allows the steam in thesmall cylinder R to escape through the ports V, T, P and O to the finalexhaust port E. At the same time pressure steam from the port D isallowed to pass through the port Z in the valve F, Fig. 4, to the smallcylinder S, and, eX- erting its force therein, to drive the valve F intothe position shown in Fig. 3. In this position the port H has cut offthe steam supply through H and is now opposite a blind port Q. Thehighpressure steam remaining on the under side of the piston K passesthrough H, H and J 2 into J J and J, to the top of the piston K where itexpands and acts on the differential area between the top of the pistonand the bottom of the piston i. e. the area of the rod L, thus causingthe pump to make the downward stroke. This rod L is made of such adiameter as will furnish sufficient area for the steam to act on tocause the pump to make its downward stroke. In most cases it is foundthat the normal dimensions of the rod are sufficient as the load on theair pump piston is so slight on its downward stroke.

Fig. 5 is a view lookingon the back of valve chest to the lower andupper ends of the cyl' G and on face N of valve F and showsthe relativepositions of valves G and F after the latter has been steam driven intothe position shown in Fig. 2. These valves are now in the requiredpositions'for the commencement of the upward stroke of the pump.

Fig. 6 is a cross vertical section of the steam distribution chest C andvalves F and G, showing the connection from small cylinder S throughport Z, cavity U, ports T, P and O, to final exhaust E. When the valve Gis at the top end of its travel, as in Fig. 4, the small cylinder R isplaced in communication with the final exhaust E through ports V, T, Pand O. The arrangement of the steam actuated valve and chest differsonly from the ordinary Weir arrangement in that no direct steam supplyport is used for the top end of the cylinder, and the main ports are soarranged as shown on the drawings that the original supply of steam tothe under side of the piston is transferred at the conclusion of theupward stroke of the piston through the valve to the upper side of thepiston, this being permissible on account of the cubical capacity of thecylinder above the'piston being somewhat larger than the cubicalcapacity below the piston due to the differential area of the rod. It isalso evident that the cavity J 4 is subject alternately to pressure andexhaust and therefore this cavity cannot be used for receiving theexhaust steam from the valve throwing motive cylinders S and R as isusually the case. The special cavity T is therefore arranged in thevalve F leading to a separate port P which communicates with the finalexhaust E by another port 0 in the steam chest for the purpose ofexhausting pressure steam from the valve throwing motive cylinders S andR.

It is quite evident that as this invention consists of the improvedarrangement of the steam ports of steam actuated valves, particularlyfor direct-acting steam driven air pumps it is applicable to any type ofsteam actuated steam distributing valve on account of its applicationbeing so simple and easily comprehended, and on this account I have onlyshown it on the drawings as applied to one well-known type of steamactuated valve.

Having now described my invention what I claim and desire to secure byLetters Iatent of the United States is 1. In a pumping apparatus, thecombination with a single acting air pump provided with a piston, ofactuating means therelor comprising a single cylinder, a steam actuatedpiston in said cylinder, a piston. rod connecting said pistons, saidpiston rod providing diil'erential areas on the opposite sides of saidsteam actuated piston, a steam actuated valve for alternately admittingsteam to the side of said steam actuated piston to which said piston rodis attached to cause said steam actuated piston to move in one directionto produce the eil'ective stroke of said pump piston, and fortransferring said steam from said last-nwntioned side to the oppositeside to cause said steam actuated piston to move in the oppositedirection to produce the idle stroke ol. said pump piston, and means,connected to said piston rod, for controlling the movements of saidvalve.

2. In a pumping apparatus, the COlllhlllfir' tion with a single-actingair pump, of actuating means therefor comprising a, cylinder havingapair of ports, a piston in said cyl inder, a piston rod connecting saidpiston and said pump, and means for alternately admitting steam to oneside of said piston to cause said piston to move in one direction toproduce the eil'ective stroke of said pump, and for permitting saidsteam to pass to the opposite side of said piston during the idle strokeof said pump, said means comprising a casing, a valve slidably mountedwithin said casing, said valve being provided with a. system of passagesadapted to control the passage of steam to and from said cylinder portsand with a second system of passages adapted to control the passage ofsteam to and from the ends of said c: sing beyond said valve, and meansconnected to said pistonrod for controlling the passage of steam to andfrom said second system 01 passages.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

INILLIAM WEIR.

Witnesses VVALLAoE Flinuvna'rnnn, JNo. ARMs'rRoNe, Jam.

